I have the shocker 228 kit and I’m having a time trying to find a key on accessory wire that will power the compressor…any ideas? My setup is in a 08 Silverado.
I have the shocker 228 kit and I’m having a time trying to find a key on accessory wire that will power the compressor…any ideas? My setup is in a 08 Silverado.
Cigarette lighter or normally there is a key on supply to radio/cd player?
Powering your compresor should only be done by wiring direct through a fuse and then to your battery. If you want to switch that circuit on/off with your accessories (ignition key) you will need to include a relay and then use a 12v ACC line (e.g. Cigarette lighter socket) as the trigger. Some cars have upfitter circuits which have relay & wiring ready to use.
The 228 kit is a little unique since it wires power directly to the compressor via the pressure switch (i.e no relay). It can afford to do so because of the relatively low amperage draw of the Viair 280C. Regardless of that you will want to be careful what you tap into in order to run that system. Refer back to my first statement if you want to stay on the safe side.
If you need help and want to wire in a relay let us know and we’ll go through what you have to do.
Get a fuse tap and go in with your radio or cigar ligjter like said above
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Merged threads…
I agree with DBO. I would not power a compressor from stock wiring or fuse panel. Use a relay and trigger it with your ignition source.
I haven’t searched my '09 for an ignition source yet, but there are a few NNBS Chevys and GMCs on the forum.
You can always go to www.the12volt.com to look up wiring by make and model so that you know which wires to tap into.
Thanks for the solutions…How would I use a relay?
OK… so basically a relay is just another switch. It gets turned on or off via an internal coil called a trigger (more about that later). There are many different types of relays but the one you will want is what’s called a Single Pole Single Throw (SPST) relay and it looks something like this:
They’re used a lot in auto electronics and switch on things like lights, horns, etc. Their primary role is to switch a high current circuit using a low current power source. On an SPST relay there are always FOUR pins and if you look at the above picture you’ll notice pins 30 & 87 are the switch part (i.e. the high amp line) and pins 85 & 86 are the coil (i.e. for the trigger; the low amp line).
Another important aspect to remember is that like ANY switch it will have a rated capacity, both in terms of volts and amperage (current). You will need to buy a relay to suit the amperage draw of your compressor. With the Viair 280C it has a maximum draw of 16 amps. So get a 12V SPST relay rated at above 16 amps.
OK… now to the fun part. The wiring of it. Basically, here’s the steps:
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You will want to find a 12V power wire in your car that switches on-off with your accessory circuit. Easy pick is the cigarette lighter plug, but there will be others and to find them it’s best to use a multimeter with sharp probes. Once found, it gets wired to the trigger pin on the relay and then out to ground/earth.
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You will want to wire the relay so that the main power line to the compressor traces through a fuse and directly onto the battery of the car.
At the relay it will be power-in, power-out. As simple as that.
Here’s a diagram to show you how you need to wire it:
Now… one additional safety note in terms of choosing trigger wires and relays. This is especially important if you find a trigger wire which you do not know what it’s used for in the car. Modern cars can be VERY sensitive to irregular voltages (e.g. the ECU or other computer boards). What happens in a relay is that the coil can send a voltage spike (many hundreds of volts) up through the trigger wire as the circuit collapses (i.e. turns off). It’s to do with the coil electrical field but I don’t want to go into it in too much depth here.
The point I wanted to make is that you MUST choose your trigger wire wisely. Using a cigarette lighter plug is a pretty safe option since that circuit will be designed to handle spikes. On the other hand if you just pick the first wire you come across and are not really sure what it’s used for, then you should wire it through a transient-voltage-suppression diode (called a transob), which basically protects that circuit from the short over-voltage.
Anyway… hope that helps. Any other questions let us know.
Ha! It works! Finally I can blow my horns!!! Thanks for all your help!
Welcome. Obviously, you came to the right place.